Printing patterns using with specific numbers in C

Question

I'm trying to create a C program that prints a triangular pattern according to height by only using 1, 2 and 3 to generate the patterns:

Enter the height:
7
Pattern:
1
22
333
1111
22222
333333
1111111

I am only able to print the numbers but I do not know how to print only using 1, 2 and 3

This is my code so far:

printf("Enter the height: \n");
scanf("%d", &height);

if(height <0 || height > 10){
    printf("Please enter height within 1 to 10!");
}
else{
    printf("Pattern: \n");

    for(row=1; row<=height; row++){
        for(int col=1; col<=row; col++){
             printf("%d", row );
        }
        printf("\n");
    }
return 0;
}

The output:

Enter the height:
7
Pattern:
1
22
333
4444
55555
666666
7777777

Thank you

Answer 1

Just change your print statement like,

printf("%d", (row % 3) > 0 ? row % 3 : 3);

Answer 2

The change would be:

for(row=1; row<=height; row++){
    int num = row%3;
    if(num==0)
        num = 3;
    for(int col=1; col<=row; col++){
         printf("%d", num );
    }
    printf("\n");
}

Logic:
1. Divide the value of row by 3 and get the remainder (i.e., perform row % 3).
2. If the remainder is 0, it means that the row number is a multiple of 3. Therefore, print 3s.
3. Otherwise, print the remainder.

Answer 3

I am only able to print the numbers but I do not know how to print only using 1, 2 and 3

This is because of you have been printing the row number in your code. There are many ways to achieve the same thing.

To solve your problem, you can have a variable (number in my program below) and keep on incrementing it in the outer for loop and once it becomes more than 3, then reset it to 1.

void print_pattern(unsigned height)
{
    unsigned row,number,column;
    for (row=0, number=1; row < height; row++) {
        for (column=0; column <= row; column++)
            printf("%u", number);

        printf("\r\n");
        if (++number > 3)
            number = 1;

    }
}

Or You can use the operator modulus %. You can apply it on row variable (see the program below) to get the the number to be printed at a particular row.

void print_pattern(unsigned height)
{
    unsigned row,column;
    for (row=0; row < height; row++) {
        for (column=0; column <= row; column++)
            printf("%u", (row % 3) + 1);

        printf("\r\n");
    }
}

Answer 4

use the mod operation % .. (number%4) is between 0 and 3 .. since you want it from 1 to 3 then take (number%3+1) ..

printf("Enter the height: \n");
scanf("%d", &height);

if(height <0 || height > 10){
   printf("Please enter height within 1 to 10!");
}
 else{
  printf("Pattern: \n");

  for(row=1; row<=height; row++){
      for(int col=1; col<=row; col++){
         printf("%d", (row%3)+1 );
    }
    printf("\n");
   }
 return 0;
}

Answer 5

#include<stdio.h>
#include<conio.h>

int main(){

    int n; int l=1;
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        int j=i;
        while(j!=0){
            printf("%d",l);

            j--;
        }
         l++;
            if(l==4){
                l=1;
            }
       printf("\n");    
    }



}